Multilayer electronics assembly and method for embedding electrical circuit components within a three dimensional module

Abstract

A multilayer electronics assembly and associated method of manufacture are provided. The multilayer electronics assembly includes a plurality of stacked substrate layers. Each of the substrate layers is fusion bonded to at least an adjacent one of the plurality of substrate layers. A first discrete electrical circuit component is bonded to a first layer of the plurality of layers. A bonding material is interposed between the discrete electrical circuit component and the first layer. The bonding material has a reflow temperature at which the bonding material becomes flowable that is higher than a fusion bonding temperature of the substrate layers.

The invention claimed is: 
     
       1. A method of embedding discrete electrical circuit components within a multilayer module, comprising:
 attaching a first discrete electrical circuit component to a first substrate via a bonding material that is initially flowable at a first temperature thereby causing the bonding material to go through a state transition such that, once the bonding material hardens, the bonding material will not return to a flowable state until a second temperature is reached, the second temperature is higher than the first temperature, the first temperature is lower than a fusion bonding temperature of the first substrate, and the second temperature is higher than the fusion bonding temperature of the first substrate, the attaching of the first discrete electrical circuit component including subjecting the bonding material to a temperature at or above the first temperature to cause the bonding material to go through the state transition and thereafter allowing the bonding material to harden to a solid state; 
 attaching a second discrete electrical circuit component to a second substrate via the bonding material, the attaching of the second discrete electrical circuit component including subjecting the bonding material to a temperature at or above the first temperature to cause the bonding material to go through the state transition and thereafter allowing the bonding material to harden to a solid state; and 
 thereafter, fusion bonding the first substrate to the second substrate at or above the fusion bonding temperature and below the second temperature such that the bonding material remains in the solid state and does not return to the flowable state during the fusion bonding. 
 
     
     
       2. The method of  claim 1 , wherein attaching the first discrete electrical circuit component to the first substrate includes nanosilver sintering the first discrete electrical circuit component to the first substrate. 
     
     
       3. The method of  claim 1 , wherein attaching the first discrete electrical circuit component to the first substrate includes transient liquid phase bonding the first discrete electrical circuit component to the first substrate. 
     
     
       4. The method of  claim 1 , further comprising:
 prior to fusion bonding the first substrate to the second substrate, stacking a plurality of substrate layers, which include the first substrate and the second substrate, in a stacking direction with the first discrete electrical circuit component overlapping the second discrete electrical circuit component in the stacking direction. 
 
     
     
       5. The method of  claim 1 , further comprising:
 prior to fusion bonding the first substrate to the second substrate, stacking a plurality of substrate layers, which include the first substrate and the second substrate, in a stacking direction with the first discrete electrical circuit component positioned between adjacent layers of the plurality of stacked substrate layers. 
 
     
     
       6. The method of  claim 1 , wherein the first discrete electrical circuit component is one of a passive discrete resistor, a capacitor, a magnetic device, and an active semiconductor device. 
     
     
       7. The method of  claim 1 , further comprising:
 prior to fusion bonding the first substrate to the second substrate, stacking a plurality of substrate layers, which include the first substrate and the second substrate, in a stacking direction; and 
 fusion bonding the plurality of substrate layers together to carry out the fusion bonding of the first substrate to the second substrate and to form a unitary block of substrate material. 
 
     
     
       8. The method of  claim 7 , wherein fusion bonding the plurality of substrate layers together includes enclosing the first discrete electrical circuit component within the unitary block of substrate material. 
     
     
       9. The method of  claim 7 , wherein fusion bonding the plurality of substrate layers together includes enclosing the first discrete electrical circuit component within the unitary block of substrate material without the unitary block of substrate material directly contacting the first discrete electrical circuit component. 
     
     
       10. The method of  claim 7 , wherein fusion bonding the plurality of substrate layers together includes enclosing each of the first discrete electrical circuit component and the second discrete electrical circuit component within the unitary block of substrate material. 
     
     
       11. The method of  claim 7 , wherein fusion bonding the plurality of substrate layers together includes enclosing each of the first discrete electrical circuit component and the second discrete electrical circuit component within the unitary block of substrate material without the unitary block of substrate material directly contacting the first discrete electrical circuit component or the second discrete electrical circuit component. 
     
     
       12. The method of  claim 7 , wherein stacking the plurality of substrate layers includes manipulating the first substrate with the first discrete electrical circuit component attached thereto and the second substrate with the second discrete electrical circuit component attached thereto relative to each other. 
     
     
       13. The method of  claim 12 , wherein, while manipulating the first substrate and the second substrate relative to each other, the first discrete electrical circuit component remains fixedly attached to the first substrate by the bonding material in a hardened state and the second discrete electrical circuit component remains fixedly attached to the second substrate by the bonding material in a hardened state. 
     
     
       14. The method of  claim 1 , further comprising:
 attaching a third discrete electrical circuit component to the first substrate via the bonding material to overlap with the first discrete electrical component in a direction that is perpendicular to a thickness direction of the multilayer module. 
 
     
     
       15. The method of  claim 1 , further comprising:
 providing a primary substrate; 
 die bonding a power semiconductor to the primary substrate; 
 prior to fusion bonding the first substrate to the second substrate, stacking the first and second substrates having the first and second discrete electrical circuit components attached thereto on the primary substrate; and 
 after fusion bonding the first substrate to the second substrate, attaching an active electrical circuit component to an external surface of a unitary block of substrate material formed by the fusion bonding. 
 
     
     
       16. The method of  claim 15 , wherein attaching the first discrete electrical circuit component to the first substrate includes nanosilver sintering the first discrete electrical circuit component to the first substrate or transient liquid phase bonding the first discrete electrical circuit component to the first substrate. 
     
     
       17. The method of  claim 15 , further comprising:
 prior to fusion bonding the first substrate to the second substrate, attaching the primary substrate to one of the first and second substrates to form a subassembly such that, when the first and second substrates are subsequently fusion bonded together, the primary substrate is fixedly attached to a unitary block of substrate material formed by the fusion bonding. 
 
     
     
       18. The method of  claim 15 , wherein stacking the first and second substrates having the first and second discrete electrical circuit components attached thereto on the primary substrate includes arranging the first discrete electrical circuit component to overlap with the second discrete electrical circuit component in a direction of the stacking. 
     
     
       19. A method of embedding discrete electrical circuit components within a multilayer module, comprising:
 attaching a first discrete electrical circuit component to a first substrate via a bonding material that is initially flowable at a first temperature thereby causing the bonding material to go through a state transition such that, after the bonding material hardens, the bonding material will not return to a flowable state until a second temperature is reached, the second temperature being higher than the first temperature, and the attaching of the first discrete electrical circuit component including subjecting the bonding material to a temperature at or above the first temperature to cause the bonding material to go through the state transition and thereafter allowing the bonding material to harden to a solid state; 
 attaching a second discrete electrical circuit component to a second substrate via the bonding material, the attaching of the second discrete electrical circuit component including subjecting the bonding material to a temperature at or above the first temperature to cause the bonding material to go through the state transition and thereafter allowing the bonding material to harden to a solid state; and 
 thereafter, bonding the first substrate to the second substrate by subjecting the first and second substrates to a temperature at or above a bonding temperature and below the second temperature such that the bonding material remains in the solid state and does not return to the flowable state during the bonding of the first and second substrates.